I would imagine that you would segment the lifting bodies so that a leak or rupture in one or even a couple wouldn't bring the whole thing crashing down. Ships don't sink from a couple leaks here and there. You would also monitor buoyancy. The tether site needs to have some sort of reel in capability for servicing.

All of your concerns seem to be addressable through proper engineering considerations.

Just tether them all together. Make a midair mesh.

As long as the crash rate isnt higher than those of airplanes i think there shouldnt be any complaints. Or are you constantly scared of a plane full of much more dangerous kerosine crashing into your house? And i dont see why it shouldnt be possible to make them as secure as or more than planes. They will surely be inspected regularly just like normal wind turbines so its just not an argument at all i think. Their location being fixed also makes them much less dangerous because you can just put them on mountains where nothing much exists.